As a conventional example, there is a charging system disclosed in, e.g., Patent Document 1. The charging system includes a charging cable unit and a display device. The charging cable unit connects a commercial power system with an emergency battery device or an electric vehicle (including a plug-in hybrid electric car), which includes a rechargeable battery, to supply charging power to the emergency battery device or the electric vehicle (hereinafter, referred to as “electric vehicle or the like”). The charging cable unit is provided with a transmission device for transmitting, between the charging cable unit and the electric vehicle or the like, charging information on the battery to the display device.
The display device receives the charging information transmitted from the transmission device of the charging cable unit, and displays the received charging information on a display such as a liquid crystal monitor. Accordingly, the charging state of the battery can be recognized even in a remote place from the electric vehicle or the like.
[Patent Document 1] Japanese Patent Application Publication No. 2010-115051.
Meanwhile, a charging current required for charging the electric vehicle or the like is usually larger than the current consumption of general electric appliances such as a television receiver, a refrigerator and an air conditioner. Therefore, when the electric vehicle or the like is charged at the same time as the electric appliances are being used, the current supplied from the power system is greatly increased. When the current supplied from the power system (current consumption) is greatly increased, an electric cable used in wirings may need to be replaced by a high capacity one or a contract demand with an electric power company may need to be changed. If no action is taken, there arises a concern that an overload current flows and thus a main breaker of a distribution board or a limiter installed by the electric power company operates to stop the power supply.
In the conventional example disclosed in Patent Document 1, it is possible to recognize the charging state of the electric vehicle or the like, but it cannot prevent the occurrence of inconvenience (the stop of the power supply, change of the contract demand, replacement of the electric cable, or the like) due to the charging of the electric vehicle or the like, as described above.